Disconnecting fuse



DISCONN ECTING FUSE Filed Aug. 3, 1931 2 SheacsmShaat INVENTOR 1iA .MW/:L

Patented Mar. 29, 1932 NETE@ STATES LESTER C. HART, OF CLEVELAND, OHIO, ASSIGNOR TO H-VOLTAGE EQUIPMENT COlrf- PANY, A CORPORATION OF OHO DISCONNECTING FUSE Application filed August 3, 1931. Serial No. 554,698.

The invention relates to fuses ot the dis- Connecting type. It has for its principal objects the provision of an improved construction adapted to prevent any leakage of current through or over the fuse tube after the fuse link has blown, and further not only to avoid such leakage, but eliminate entirely any diiference in potential between the two ends of the fuse tube. One embodiment ot the invention is shown in the accompanying drawings, wherein:

Figure 1 is a perspective view showing the fuse in closed position. Fig. 2 is a similar view showing the switch in open position.

An d Fig. 3 is a side elevation showing a modication.

Referring to the drawings, 1 is the metal base ot' the device provided at its ends with the insulators 2 and 3 rigidly secured thereto. The insulators carry the metal pins 4 and 5 whose upper portions 6 and 7 serve as conductor terminals to which the leads 8 and 9 are connected.

The terminal 7 is also provided with an extension or bracket 10 to which is hinged the metal cap 11 ot the switch arm 12, such arm being of insulating material such as porcelain or other suitable material. The termin al 7 is also provided with a pair ot' spring Contact lips 13 adapted to make electrical contact with the base 14 of the cap when the switch arm is in closed position.

The other end of the switch arm is also provided with a metal cap 15 hereafter referred to as a block to distinguish it from the first mentioned cap. This block 15 is also provided with a base portion 16 adapted to be received between the spring clips 17 on the terminal when the switch arm is in closed position.

The upper part 18 of the block 15 is of cylindrical shape to receive the end of the fuse tube 19. This fuse tube is of insulating material, such as bakelite, and is screwed into the part 18. The tube carries the fuse wire 2O which at one end makes electrical ccntact with the cap piece 21 of the part 18. The other end of the wire extends through the open end of the fuse tube and is connected at its end to the cap 11 by means of the clamp- "all ing nut 22 on the stud 23. rthis tube and fuse are similar in construction to that shown in my Patent No. 1,605,543, granted November 2, 1926.

'Vhen the fuse blows, there is no tendency ot the current to creep along the charred fuse tube, since the air gap at the tree end of the tube eliminates tais tendency. The eect is substantially different from that which eX- ists when the free end of the tube is supported by an insulator which separates it from the conductor as in this case there is always this tendency, and although the amount of current traversing the tube is very small, it is sutiicient to set up serious radio interference. TWith the present construction nothing ot this kind occurs, and the fuse tube is not subjected to any potential diterence after the fuse blow. The arm 12 is of material chosen for its insulating value and takes the entire voltage stress.

1n the modified structure shown in Fig. 3, the change as compared with the structure of Figs. 1 and 2, resides in the reverse arrangement of the fuse tube 19a such fuse tube being mounted at the hinged end ot the switch arm 12 instead of at the free end. The tube is supported on the block or cap 15a corresponding to the cap 15 of Figs. 1 and 2, the free end of the arm 12 being provided with a. cap or block 11a which makes engagement with the clips 17a on the terminal 6. The cap 15a also makes engagement with the clips 13a on the other terminal 7a. In both constructions, a spring pressed latch 24 engaging a hook on the terminal block serves to releasably lock the switch arm in closed position. The same reference numerals are employed on Fig. 3 as on Figs. 1 and 2 to designate similar parts.

Vhat I claim is:

1. In combination in a fuse construction, a pair of spaced insulators each carrying a conductor terminal, a switch arm of insulating material provided at its ends with blocks ot' conducting material one of which is hinged to one terminal and the other of which is adapted to make electrical contact with the terminal carried by the other insulator, a fuse tube ofl insulating material supported at one end by one of said blocks with its other end free and extending along said switch arm but spaced away therefrom, and a fusible member in the tube having its ends connected to said blocks.

2. In combination in a fuse construction, a pair of spaced insulators each carrying a conductor terminal, a switch arm of insulating material hinged to one terminal and provided at its otherl end with a. block of conducting material adapted to make electrical contact with the terminal lcarried by the other insulator, a fuse tube of insulating material supported at one end by said block with its other end free and extending along said switch arm but spaced away therefrom, and a fusible member in the tube having one end connected to said block and its other end connected to the terminal at the hinged end of the switch arm.

3.Y In combination in a fuse construction, a pair of spaced insulators each carrying a conductor terminal, a switch arm of insulating material hinged to one terminal and provided at its other end with a block of conducting material adapted to make electrical contact with the terminal carried by the other insulator, a fuse tube of insulating material supported at one end by said block with its other end free and extending along said switch arm but inclined away from said switch arm, and a fusible member in the tube having one end connected to said block and its other end connected to the terminal at the hinged end of the switch arm.

a. In combination in a fuse construction, apair of spaced insulators each carrying a conductor terminal, a switch arm of insulating material provided with a metal cap at one end hinged to one of said terminals and a metal block at its other end adapted to make electrical contact with the other terminal when the switch arm is in closed position, a fuse tube of insulating material supported at one end by said block with its other end free and extending along such switch arm but spaced away therefrom, and a fusible member in the tube having one end connected to said block and the other end connected to said cap.

5. In combination in a fuse construction, a pair of spaced insulators each carrying a conductor terminal, a switch arm of insulating material provided with a metal cap at one end hinged to one of said terminals and Vadapted to make a sliding electrical contact therewith when ,the switch arm is in closed position, a metal block carried by the other end of the switch arm adapted to make electrical contact with the other terminal when the switch arm is in closed position, a fuse tube of insulating material supported at one end by said block with its other end free and extend-V ing along such switch arm but spaced away therefrom, and a fusible member in the tube having one end connected to said block and the other end connected to said cap.

6. In combination in a fuse construction, a pair of spaced insulators each carrying a conductor terminal, a. switch arm of insulating material provided at its ends with blocks of conducting materia-l one of which is hinged to one terminal and the other of which is adapted to makeelectrical contact with the terminal carried by the other insulator, a fuse tube of insulating material supported at one end onV the block which is hinged to said terminal with its other end free and extending along said switch arm, but spaced away therefrom, and a fusible member in the tube having its ends connected to said blocks.

In testimony whereof, I have hereunto subscribed my name this 31 day of July, 1931.

LESTER C. HART. 

